Fischertechnik CNC Machine Looks Innocent Whilst Cutting Your Face

FischerTechnik + Arduino CNC Milling Machine

Hallo iedereen! All the way from the Netherlands comes this fairly unique CNC milling machine built by a handful of Mechanical Engineering students over at the Delft University of Technology. These guys only had one week to build the mill in order to fulfill a requirement of their Mechtronics class. Unfortunately, directly after showing the machine worked, it had to be disassembled.

If the frame looks a little toy-ish, it’s because it is. This particular system is called Fischertechnik and the main support beams are similar to that of aluminum extrusion (ex 80/20, Misumi) except that it is made from nylon. Notice the extremely long cutting bit and comparatively abnormal large Z axis travel capability. What this system lacks in rigidity is made up by being able to carve a very 3D shape with steep sides without the machine hitting the work piece. The loss of rigidity was totally acceptable since the team was only planning on cutting foam and the project’s purpose was to learn mechanics and automation.

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Electricity Monitoring with a Light-to-Voltage Sensor, MQTT and some Duct Tape


When it comes down to energy management, having real-time data is key. But rarely is up-to-the-minute kilowatt hour information given out freely by a Utility company, which makes it extremely hard to adjust spending habits during the billing cycle. So when we heard about [Jon]‘s project to translate light signals radiating out of his meter, we had to check it out.

From the looks of it, his hardware configuration is relatively simple. All it uses is a TSL261 Light-to-Voltage sensor connected to an Arduino with an Ethernet shield attached. The sensor is then taped above the meter’s flashing LED, which flickers whenever a pulse is sent out indicating every time a watt of electricity is used. His configuration is specific to the type of meter that was installed by his Utility, and there is no guarantee that all the meters deployed by that company are the same. But it is a good start towards a better energy monitoring solution.

And the entire process is documented on [Jon]’s website, allowing for more energy-curious people to see what it took to get it all hooked up. In it, he describes how to get started with MQTT, which is a machine-to-machine (M2M)/”Internet of Things” connectivity protocol, to produce a real-time graph, streaming data in from a live feed.

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Milling Curved Objects With A G-Code Ripper

HaD Mouse

Milling and routing flat surfaces is pretty much the point of a CNC router, but how about curved surfaces? Auto leveling of hobby CNC machines and 3D printers is becoming commonplace, but Scorch Works is doing just the opposite: using a probe touch probe on a CNC machine to transform a G-Code file into something that can be milled on a curved surface.

The technique is pretty much the complete opposite of Autoleveller, the tool of choice for milling and routing objects that aren’t completely flat or perpendicular to the bed with a MACH3 or LinuxCNC machine. In this case, a touch probe attached to the router scans a curved part, applies bilinear interpolation to a G-Code file, and then starts machining.

The probe can be used on just about anything – in the videos below, you can see a perfect engraving in a block of plastic that’s about 30 degrees off perpendicular to the bed, letters carved in a baseball bat, and a guaranteed way to get your project featured on Hackaday.

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An Excel Based High Frequency Transistor Amplifier Calculator

amplifier calculator


[Paulo] just tipped us about an Excel based high frequency transistor amplifier calculator he made. We’re guessing that some of our readers already are familiar with these class A amplifiers, commonly used to amplify small audio signals. Skipping over the fact that their efficiency is quite low — they are cheap to make, don’t require many components and usually are a great way to introduce transistors to new electronics enthusiasts. All you usually need to do is a few calculations to properly set your output signals and you’re good to go.

Things are however more complex when you are amplifying 200MHz+ signals, as all the components (complex) impedances have to be taken into account so you can get a nice amplification system. On a side note, at these frequencies your transmission lines impedances may even vary depending on how much solder and flux you left on your SMT pads along the way. [Paulo]‘s calculator will therefore compute most of the characteristics of two class A common emitter/collector amplifiers for specified loads.


PS/2 Synth Will Knock You Off Your Broom


Here’s a hack centered around something a lot of people have sitting around: a PS/2 keyboard. [serdef] turned a Harry Potter-edition PS/2 into a combination synth keyboard and drum machine and has a nice write-up about it on

For communication, he tore up a PS/2 to USB cable to get a female mini DIN connector and wired it to the Nano. He’s using a Dreamblaster S1 synth module to generate sounds, and that sits on a synth shield along with the Nano. The synth can be powered from either the USB or a 9-volt.

Keymapping is done with the Teensy PS/2 keyboard library. [serdef] reused a bunch of code from his bicycle drummer project which also employed the Dreamblaster S1. [serdef] is continually adding features to this project, like a pot for resonance control which lets him shape the waveform like an analog synth. He has posted some handy PS/2 integration code, his synth code, and a KiCad schematic. Demo videos are waiting for you across the link.  [Read more...]

DIY USB Spectrometer Actually Works

image of diy spectrometer

When we hear spectrometer, we usually think of some piece of high-end test equipment sitting in a CSI lab. Sure, a hacker could make one if he or she put their mind to it. But make one out of a webcam, some cheap diffraction grating purchased off ebay and some scrap? Surely not.

[Renaud] pulls off this MacGyver like build with a detailed knowledge of how spectrometers work. A diffraction grating is used to split the incoming light into its component wavelengths. Much like a prism would. The wavelengths then make their way through a slit, which [Renaud] made from two pieces of highly polished brass, so the webcam sensor can see a specific wavelength. While the spectrometer-from-webcam concept isn’t new,  the build is still impressive.

Once the build was complete, [Renaud] put together some software to make sense of the data. Though a bit short on details, we hope this build will inspire you to make your own spectrometer, and document it on of course.

ZX Spectrum Turned Into A USB Keyboard


They’re a little hard to find in the US, but the ZX Spectrum is right up there with the Commodore 64 and the Atari 8-bit computers in England. [Alistair] wanted to recreate the feeling of sitting right in front of the TV with his Speccy, leading him to create the ZX Keyboard, a Spectrum repurposed into a USB keyboard.

While most projects that take an old key matrix and turn it into a USB keyboard use the TMK firmware, [Alistair] wanted to flex his programming muscles and wrote the firmware from scratch. It runs on an Arduino Pro Mini, scanning the matrix of five columns and eight half rows to turn combinations of keypresses into an astonishing number of commands, given the limited number of keys on the ZX.

The firmware is available on [Alistair]‘s repo, available to anyone who doesn’t want to pay the £50 a new ZX Spectrum keyboard will cost. As far as the usability of a Spectrum keyboard goes, at least [Alistair] didn’t have an Atari 400 sitting in the attic.